- Fix /etc/resolv.conf change detection for multi-threaded applications

(by Sebastian Kienzl)

OBS-URL: https://build.opensuse.org/package/show/Base:System/glibc?expand=0&rev=20

glibc-2.4.90-nscd.diff

@@ -1,7 +1,7 @@
 Index: nscd/cache.c
 ===================================================================
---- nscd/cache.c.orig
+--- nscd/cache.c.orig	2010-01-18 18:01:41.000000000 +0100
-+++ nscd/cache.c
++++ nscd/cache.c	2010-02-14 14:58:08.000000000 +0100
 @@ -267,28 +267,31 @@ prune_cache (struct database_dyn *table,
    if (table->inotify_descr < 0 && table->check_file && now != LONG_MAX)
      {
@@ -47,8 +47,8 @@ Index: nscd/cache.c
       Note that for the initial step, finding the entries to be removed,
 Index: nscd/connections.c
 ===================================================================
---- nscd/connections.c.orig
+--- nscd/connections.c.orig	2010-01-18 18:01:41.000000000 +0100
-+++ nscd/connections.c
++++ nscd/connections.c	2010-02-14 14:58:08.000000000 +0100
 @@ -119,6 +119,7 @@ struct database_dyn dbs[lastdb] =
      .suggested_module = DEFAULT_SUGGESTED_MODULE,
     .reset_res = 0,
@@ -94,8 +94,8 @@ Index: nscd/connections.c
  
 Index: nscd/nscd.conf
 ===================================================================
---- nscd/nscd.conf.orig
+--- nscd/nscd.conf.orig	2010-01-18 18:01:41.000000000 +0100
-+++ nscd/nscd.conf
++++ nscd/nscd.conf	2010-02-14 14:58:08.000000000 +0100
 @@ -61,11 +61,11 @@
  	auto-propagate		group		yes
  
@@ -113,8 +113,8 @@ Index: nscd/nscd.conf
  
 Index: nscd/nscd.h
 ===================================================================
---- nscd/nscd.h.orig
+--- nscd/nscd.h.orig	2010-01-18 18:01:41.000000000 +0100
-+++ nscd/nscd.h
++++ nscd/nscd.h	2010-02-14 14:59:07.000000000 +0100
 @@ -80,8 +80,10 @@ struct database_dyn
    int propagate;
    int reset_res;
@@ -128,9 +128,24 @@ Index: nscd/nscd.h
  
 Index: nscd/nscd_stat.c
 ===================================================================
---- nscd/nscd_stat.c.orig
+--- nscd/nscd_stat.c.orig	2010-01-18 18:01:41.000000000 +0100
-+++ nscd/nscd_stat.c
++++ nscd/nscd_stat.c	2010-02-14 15:02:41.000000000 +0100
-@@ -302,7 +302,7 @@ receive_print_stats (void)
+@@ -37,8 +37,13 @@
+ #endif /* HAVE_SELINUX */
+ 
+ 
+-/* We use this to make sure the receiver is the same.  */
++/* We use this to make sure the receiver is the same.  Capture mtime
++   of this file if possible.  */
++#if defined(__TIMESTAMP__)
++static const char compilation[21] = __TIMESTAMP__;
++#else
+ static const char compilation[21] = __DATE__ " " __TIME__;
++#endif
+ 
+ /* Statistic data for one database.  */
+ struct dbstat
+@@ -302,7 +307,7 @@ receive_print_stats (void)
  	      data.dbs[i].maxnsearched,
  	      data.dbs[i].rdlockdelayed,
  	      data.dbs[i].wrlockdelayed,

glibc-resolv-reload.diff

@@ -0,0 +1,124 @@
+From libc-alpha-return-22754-pasky=ucw.cz@sourceware.org  Tue Mar 16 00:47:00 2010
+Return-Path: <libc-alpha-return-22754-pasky=ucw.cz@sourceware.org>
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+Message-ID: <4B9E6CFA.7020002@riot.org>
+Date: Mon, 15 Mar 2010 18:23:06 +0100
+From: Sebastian Kienzl <seb@riot.org>
+User-Agent: Thunderbird 2.0.0.23 (Windows/20090812)
+MIME-Version: 1.0
+To: libc-alpha@sourceware.org
+Subject: Reloading of /etc/resolv.conf
+Content-Type: multipart/mixed;
+ boundary="------------060407080409020101000002"
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+
+This is a multi-part message in MIME format.
+--------------060407080409020101000002
+Content-Type: text/plain; charset=ISO-8859-15; format=flowed
+Content-Transfer-Encoding: 7bit
+
+Hello!
+
+There's a patch in the wild against the resolver which makes it reload
+/etc/resolv.conf on change, see
+http://sources.redhat.com/ml/libc-alpha/2004-09/msg00130.html
+
+However, this patch actually doesn't work properly for multi-threaded
+programs, as only one thread will notice the change and refresh its
+resolver state. I've attached a proper patch. It's for 2.5 but it should
+work with current versions, too.
+
+Even though the patch may not be interesting for upstream, I decided to
+let you know about this problem, since the mentioned patch seems to be
+used by at least Debian and Ubuntu.
+
+Regards,
+Seb.
+
+
+
+--------------060407080409020101000002
+Content-Type: text/plain;
+ name="glibc-2.5-resolvconf.patch"
+Content-Transfer-Encoding: 7bit
+Content-Disposition: inline;
+ filename="glibc-2.5-resolvconf.patch"
+
+diff -ur resolv.orig/res_libc.c resolv/res_libc.c
+--- resolv.orig/res_libc.c	2005-11-01 01:06:40.000000000 +0100
++++ resolv/res_libc.c	2010-03-15 14:13:18.000000000 +0100
+@@ -22,7 +22,7 @@
+ #include <arpa/nameser.h>
+ #include <resolv.h>
+ #include <bits/libc-lock.h>
+-
++#include <sys/stat.h>
+ 
+ /* The following bit is copied from res_data.c (where it is #ifdef'ed
+    out) since res_init() should go into libc.so but the rest of that
+@@ -89,12 +89,34 @@
+ 	return (__res_vinit(&_res, 1));
+ }
+ 
++static time_t resconf_mtime;
++__libc_lock_define_initialized (static, resconf_mtime_lock);
++
++/* Check if the modification time of resolv.conf has changed.
++   If so, have all threads re-initialize their resolver states */
++static void
++__res_check_resconf (void)
++{
++	struct stat statbuf;
++	if (stat (_PATH_RESCONF, &statbuf) == 0) {
++		__libc_lock_lock (resconf_mtime_lock);
++		if (statbuf.st_mtime != resconf_mtime) {
++			resconf_mtime = statbuf.st_mtime;
++			atomicinclock (lock);
++			atomicinc (__res_initstamp);
++			atomicincunlock (lock);
++		}
++		__libc_lock_unlock (resconf_mtime_lock);
++	}
++}
++
+ /* Initialize resp if RES_INIT is not yet set or if res_init in some other
+    thread requested re-initializing.  */
+ int
+ __res_maybe_init (res_state resp, int preinit)
+ {
+ 	if (resp->options & RES_INIT) {
++		__res_check_resconf ();
+ 		if (__res_initstamp != resp->_u._ext.initstamp) {
+ 			if (resp->nscount > 0) {
+ 				__res_iclose (resp, true);
+
+
+--------------060407080409020101000002--

glibc.changes

@@ -1,3 +1,14 @@
+-------------------------------------------------------------------
+Thu Mar 18 14:29:42 CET 2010 - pbaudis@suse.cz
+
+- Fix /etc/resolv.conf change detection for multi-threaded applications
+  (by Sebastian Kienzl)
+
+-------------------------------------------------------------------
+Sun Feb 14 15:33:33 CET 2010 - rguenther@suse.de
+
+- avoid spurious differences in nscd on rebuilds.
+
 -------------------------------------------------------------------
 Mon Jan 25 17:35:25 CET 2010 - meissner@suse.de
 

glibc.spec

@@ -82,7 +82,7 @@ NoSource:       0
 Patch0:         glibc-2.3-SuSE.diff
 Patch1:         glibc-2.3.90-noversion.diff
 Patch2:         glibc-2.3.90-fnmatch.diff
-Patch3:         resolv.dynamic.diff
+Patch3:         glibc-resolv-reload.diff
 Patch4:         glibc-2.3.locales.diff.bz2
 Patch5:         crypt_blowfish-1.0-suse.diff
 Patch7:         glibc-version.diff
@@ -310,9 +310,14 @@ rm sysdeps/x86_64/fpu/s_sincos.S
 %patch20
 %patch21
 %patch22
+# avoid changing nscd_stat.c mtime to avoid code generation
+# differences on each rebuild
+touch -r nscd/nscd_stat.c nscd/s-stamp
 %patch23
 %patch24
 %patch25
+touch -r nscd/s-stamp nscd/nscd_stat.c
+rm nscd/s-stamp
 %patch26
 %patch27
 %patch29
@@ -359,12 +364,13 @@ rm sysdeps/x86_64/fpu/s_sincos.S
 #
 rm -fv sysdeps/powerpc/powerpc32/power4/hp-timing.c sysdeps/powerpc/powerpc32/power4/hp-timing.h
 find . -name configure | xargs touch
+
+
 #######################################################################
 ###
 ### BUILD
 ###
 #######################################################################
-
 %build
 if [ -x /bin/uname.bin ]; then
 	/bin/uname.bin -a
@@ -436,6 +442,7 @@ PARALLEL="%{?jobs:-j%jobs}"
 	# fails to build otherwise - need to recheck and fix
 	%define enable_stackguard_randomization 0
 %endif
+
 configure_and_build_glibc() {
 	local dirname="$1"; shift
 	local cflags="$1"; shift
@@ -459,6 +466,7 @@ configure_and_build_glibc() {
 	make $PARALLEL
 	cd ..
 }
+
 %if !%{optimize_power}
 	#
 	# Build base glibc
@@ -488,10 +496,12 @@ configure_and_build_glibc() {
 		configure_and_build_glibc ppc-cell-be "$BuildFlags -mcpu=cell" "$add_ons" --disable-runbinaries
 	%endif
 %endif # optimize_power
+
 #
 # Build html documentation
 #
 make -C cc-base html
+
 #
 # Build glibc_post_upgrade binary
 #
@@ -510,6 +520,8 @@ $BuildCC -static -Os -g $RPM_SOURCE_DIR/glibc_post_upgrade.c -o glibc_post_upgra
  %endif
 %endif
     '-DLIBDIR="/%{_lib}"' '-DGCONV_MODULES_DIR="%{_prefix}/%{_lib}/gconv"'
+
+
 #######################################################################
 ###
 ### CHECK
@@ -531,6 +543,8 @@ $BuildCC -static -Os -g $RPM_SOURCE_DIR/glibc_post_upgrade.c -o glibc_post_upgra
 	%endif
 %endif
 make -C cc-base check-abi || echo check-abi failed
+
+
 #######################################################################
 ###
 ### INSTALL
@@ -548,12 +562,15 @@ make -C cc-base check-abi || echo check-abi failed
 # debugging tools currently require these sections directly inside the main
 # files - specifically valgrind and PurifyPlus.
 export STRIP_KEEP_SYMTAB=*.so*
+
 # Make sure we will create the gconv-modules.cache
 mkdir -p $RPM_BUILD_ROOT%{_libdir}/gconv
 touch $RPM_BUILD_ROOT%{_libdir}/gconv/gconv-modules.cache
+
 # Install base glibc
 # Do not install in parallel, timezone Makefile will fail
 make install_root=$RPM_BUILD_ROOT install -C cc-base
+
 # Install power-optimized glibc
 %if %{optimize_power}
 	# run ldconfig to create the library symlinks
@@ -592,6 +609,7 @@ make install_root=$RPM_BUILD_ROOT install -C cc-base
 		fi
 	%endif
 %endif # optimize_power
+
 # Install locales
 %if %{build_locales}
 	# Do not install locales in parallel!
@@ -601,31 +619,45 @@ make install_root=$RPM_BUILD_ROOT install -C cc-base
 %endif
 # Create file list for glibc-locale package
 %{find_lang} libc
+
 # Prepare obsolete/, used only on some architectures:
 export RPM_BUILD_ROOT
 mkdir -p $RPM_BUILD_ROOT/%{_lib}/obsolete
+
 # NPTL <bits/stdio-lock.h> is not usable outside of glibc, so include
 # the generic one (RH#162634)
 cp -av bits/stdio-lock.h $RPM_BUILD_ROOT%{_prefix}/include/bits/stdio-lock.h
+
 %ifarch s390x
 	# s390x is different ...
 	mkdir $RPM_BUILD_ROOT/lib
 	ln -sf ../%{_lib}/ld-%{version}.so $RPM_BUILD_ROOT/lib/ld64.so.1
 %endif
+
+
 # Miscelanna:
+
 install -m 0700 glibc_post_upgrade $RPM_BUILD_ROOT%{_sbindir}
+
 install -m 644 $RPM_SOURCE_DIR/bindresvport.blacklist $RPM_BUILD_ROOT/etc
 install -m 644 $RPM_SOURCE_DIR/nsswitch.conf $RPM_BUILD_ROOT/etc
 install -m 644 posix/gai.conf $RPM_BUILD_ROOT/etc
+
 mkdir -p $RPM_BUILD_ROOT/etc/default
 install -m 644 nis/nss $RPM_BUILD_ROOT/etc/default/
+
 mkdir -p $RPM_BUILD_ROOT/usr/include/resolv
 install -m 0644 resolv/mapv4v6addr.h $RPM_BUILD_ROOT/usr/include/resolv/
 install -m 0644 resolv/mapv4v6hostent.h $RPM_BUILD_ROOT/usr/include/resolv/
+
 mkdir -p $RPM_BUILD_ROOT/usr/share/doc/glibc
 cp -p manual/libc/*.html $RPM_BUILD_ROOT/usr/share/doc/glibc
+
 cd manpages; make install_root=$RPM_BUILD_ROOT install; cd ..
+
+
 # nscd tools:
+
 cp nscd/nscd.conf $RPM_BUILD_ROOT/etc
 mkdir -p $RPM_BUILD_ROOT/etc/apparmor.d
 cp $RPM_SOURCE_DIR/usr.sbin.nscd $RPM_BUILD_ROOT/etc/apparmor.d
@@ -635,6 +667,7 @@ ln -sf /etc/init.d/nscd $RPM_BUILD_ROOT/usr/sbin/rcnscd
 mkdir -p $RPM_BUILD_ROOT/var/run/nscd
 touch $RPM_BUILD_ROOT/var/run/nscd/{passwd,group,hosts}
 touch $RPM_BUILD_ROOT/var/run/nscd/{socket,nscd.pid}
+
 #
 # Create ld.so.conf
 #
@@ -674,23 +707,29 @@ mkdir -p $RPM_BUILD_ROOT/var/cache/ldconfig
 # Empty the ld.so.cache:
 rm -f $RPM_BUILD_ROOT/etc/ld.so.cache
 touch $RPM_BUILD_ROOT/etc/ld.so.cache
+
 # libNoVersion belongs only to glibc-obsolete:
 %ifarch %ix86
 	rm -f $RPM_BUILD_ROOT%{_libdir}/libNoVersion*
 	mkdir -p $RPM_BUILD_ROOT/%{_lib}/obsolete/noversion
 	mv -v $RPM_BUILD_ROOT/%{_lib}/libNoVersion* $RPM_BUILD_ROOT/%{_lib}/obsolete/noversion/
 %endif
+
 # Don't look at ldd! We don't wish a /bin/sh requires
 chmod 644 $RPM_BUILD_ROOT/usr/bin/ldd
+
 # Remove timezone data, now coming in standalone package:
 for i in sbin/sln usr/bin/tzselect usr/sbin/zic usr/sbin/zdump etc/localtime; do
 	rm -f $RPM_BUILD_ROOT/$i
 done
 rm -rf $RPM_BUILD_ROOT/usr/share/zoneinfo
+
 # Remove the buildflags tracking section and the build-id
 for o in $RPM_BUILD_ROOT/%{_libdir}/crt[1in].o $RPM_BUILD_ROOT/%{_libdir}/lib*_nonshared.a; do
 	objcopy -R ".comment.SUSE.OPTs" -R ".note.gnu.build-id" $o
 done
+
+
 #######################################################################
 ###
 ### ...
@@ -727,13 +766,15 @@ done
 %restart_on_update nscd
 %insserv_cleanup
 exit 0
+
+
 #######################################################################
 ###
 ### FILES
 ###
 #######################################################################
-# glibc
 
+# glibc
 %files
 %defattr(-,root,root)
 %doc LICENSES

resolv.dynamic.diff

@@ -1,33 +0,0 @@
-Index: resolv/res_libc.c
-===================================================================
---- resolv/res_libc.c.orig
-+++ resolv/res_libc.c
-@@ -22,6 +22,7 @@
- #include <arpa/nameser.h>
- #include <resolv.h>
- #include <bits/libc-lock.h>
-+#include <sys/stat.h>
- 
- 
- /* The following bit is copied from res_data.c (where it is #ifdef'ed
-@@ -95,6 +96,20 @@ int
- __res_maybe_init (res_state resp, int preinit)
- {
- 	if (resp->options & RES_INIT) {
-+		static time_t last_mtime, last_check;
-+		time_t now;
-+		struct stat statbuf;
-+		
-+		time (&now);
-+		if (now != last_check) {
-+			last_check = now;
-+			if (stat (_PATH_RESCONF, &statbuf) == 0 && last_mtime != statbuf.st_mtime) {
-+				last_mtime = statbuf.st_mtime;
-+				atomicinclock (lock);
-+				atomicinc (__res_initstamp);
-+				atomicincunlock (lock);
-+			}
-+		}
- 		if (__res_initstamp != resp->_u._ext.initstamp) {
- 			if (resp->nscount > 0)
- 				__res_iclose (resp, true);